1. Field of the Invention
The present invention relates to a card device for wireless communication to be loaded in a mobile communication terminal, and the mobile communication terminal.
2. Description of the Related Art
It is common that, in a mobile communication terminal such as a cellular phone, a wireless communication function such as an infrared transmission/reception function, a Bluetooth (registered trademark) function or such for short distance data transfer, is mounted. Furthermore, it is desired that, in the mobile communication terminal, a wireless LAN (Local Area Network) function for middle distance data transfer be additionally mounted.
In a case where a wireless LAN function is additionally mounted in the mobile communication terminal, a circuit block having a wireless LAN function including an antenna is mounted on a card device such as a microSD card, for example; the card device is thus used as a wireless LAN card, and the wireless LAN card is mounted in the mobile communication terminal.
It is noted that a technique is known in which an antenna for a card device is provided in a mobile communication terminal, and the antenna is connected to the card device in a case where the card device is loaded in the mobile communication terminal (see Japanese Laid-Open Patent Application No. 2009-60160, for example).
A position at which the wireless LAN card is loaded in the mobile communication terminal is different depending on a particular device type of the mobile communication terminal. In the case where the circuit block of the wireless LAN function including the antenna is mounted on the wireless LAN card, there may be a case where the antenna of the wireless LAN card is covered by a user who holds the mobile communication terminal, or the antenna of the wireless LAN card is covered by a battery pack, a circuit substrate or such of the mobile communication terminal. In such a case, sensitivity of the antenna may be degraded, and the wireless LAN function may not be used effectively.
Further, generally speaking, mobile communication carried by the mobile communication terminal may be influenced by multipath. Especially, for a frequency band of 2.4 GHz used by wireless LAN, the influence of multipath may become remarkable.